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Feb. 6, 1923. 11,444,212,

' I a. J. SEISS. INSULATED KNOB FOR RADIO INSTRUMENTS.

FILED JUNE 9,1922.

[ENT UR GEGRGE J. SEISB, OE TOLEDQ, QHIQ.

narrate TATENT @FF'HGJF...

' INSULATED KNQB FOR RADIO INSTRUEIZENTS.

Application filed June a, mac. serial No. 568,966.

To all whom it may concern Be it known that I. Gnoncn J. Sniss, a citizen of the United States. and a resident of Toledo, in the county of Lucas and State of Ohio. have made an invention appertaining to an Insulated Knob for Radio Instruments; and i do hereby declare the following to be a full, clear, and exactdescription' of the invention. such as will enable others skilled in the art to which it appertalns to make and use the same. reference being had to the acconi anying drawings, and to the characters. of reference marked thereon, which form a part of this specification.

My invention has for its object to provide a simple and yet ctiicient insulating knob for radio instruments. It is used articularly for adjustably locating movab e parts of radio instruments and positioning such parts to obtain the best results'in her well known in the art.

The invention may e used in connection with insulated knobs of different forms. To illustrate a practical application of the invention I have selected a knob embodying the invention and shall describe it hereinafter. The knob selected is illustrated in the accompanying drawings.

Figure l of the drawings is a front view of the knob. Fig. 2 is a sectional view taken on the line 2 2. Fig. 3 illustrates a side view of a means for connecting the shank or rod to the knob.

The knob 1 comprises a shell 2 that may be formed of sheet material, such as sheet metal, that may be readily stamped and manipulated in the manner well known in the arts of sheet metal stamping, spinning and drawing. Thus the knob may be very easily made by the ordinary die press and spinning devices or machines. The periphthe manera-l portion 3 is raised to form a ridge of The central portion at is lens shaped, the

other side being convex and forming with the peripheral ortion of the knob an annular recess 5 in t e outer surface of the knob and a distinct ridge 6 on the inside, and within the area defined by the ridge 3. A disc 7, which is formed of sheet insulating material Thus a grip-- such as fibre board, that may be readily formed by a die press, is located within the edge portion of the sheet material forming the shell 2. The disc 7 substantially fits withln the edge portion of the shell and is placed against the ridge tl-which is located well within the periphery of the disc 7. The edgev of the shell is spun down over and against the edge )Oli-lOIl of the disc'l. whereby the disc 7 is c amped and elastically held between the edge the ridge 6, which tightly secures the disc 7 1n ositlon.

7 means is secured to the disc 7 for connecting the knob to its shank or to a shaft to be manipulated by the knob. The corn nesting means is so formed that the knob may be readily connected to the movable shaft of an adjustable art of a radio apparatus, for example. 7 he connector 8 may be formed of any suitable metal, such as against the surface of the hole formed in the disc 7 and so that the teeth or ridges or corrugated surface 11 will engage the disc 7. Thus the disc 7 will be securely keyed to the connector 8. The inner edge 12 of the connector is s un or bent down over the edge of the hole ormed in the disc 7 and thus the disc 7 is tightly clam ped between the turned edge 12 and the shoulder 13 formed on the connector. The convex shape of the central portion of the shell 2 thus not onl forms the distinct ridge for elastically hold ing the disc 7, but also prevents electrical contact between the shell 2 and the connector 8. Y

The outer end of the connector 8 may be threaded, whereby the knob may be thread ed on the end of a shaft 14 and thus the knob may be securely connected to the movable element or rotor of the part of the radio instrument or other electrical instr'u ment for the purpose of setting or adjusting such movable part.

I claim;

1. In an insulated knob, a shell'having an inwardly extending ridge, a disc of i'nsu lating material clamped between the edge of ill) portions of the shell 2 and Nil -' clamped between the edge of the shell and the ridge, a rod, means forconnectingthe insulating disc with the rod and secured to an inwardly extending ridge, a disc of inthe shell and the. ridge, a rod, means for sulating material clamped between the edge connecting the insulating disc with the rod. of the shell and the ridge, a connector hav- 2. In an insulated k nob, a shell havin an inwardly extending ridge and a raised central portion, a'disc of insulating material and a shoulder for clamping the connector to the disc, a rod connected to the connector. 5. In an insulated knob, a shell having an inwardly extending ridge and a raised the disc within the area of the raised porcentral portion, a disc of insulating material tion of the shell. clamped between the edge of the shell and 3.'- In an insulated knob, a shell having the ridge, a connector having a corrugated an inwardly extending ridge, a disc of in-' surface for keying the connector to the disc, sulating material clam ed between the edge\ and having a turned edge and a shoulder of the shell and the ri ge, a connector havor clamping the connector to the disc, a rod ing ridges for keyin the connector to the connected to the connector. disc, a'rod connecte to the connector. In testimony whereof, I have hereunto 4. In an insulated knob, a shell having signed my name to this specification.

' GEORGE J. SEISS.

ing a corrugated surface for. keying the connector to the disc, and having aturned edge 

